The present invention relates to the construction of pianos and in particular to the sound board of a piano.
It is well known that pianos are constructed so that the sounds produced conform to the values of the Diatonic Scale or "natural" notes following the harmonic ratios: 1. --9/8--5/4--4/3--3/2--5/3--15/8--2. These values are successively doubled till that of the last string of the piano, or highest pitch encompassed, is of the value 271.257, usually the lowest sound, i.e. the first string is chosen to be 5/3, and the total number of strings employed is 88.
The internal values of the successive scales, or "Octaves" are modified in what is referred to as the "Equal Temperment Tuning" by the geometrical division of each octave into twelve equal parts, which division supposedly contains the eight "natural" notes of the scale plus an altered version of all of them but two. Thus there is finally obtained a geometrical series of values equal to the 12th root of 2. This is the method employed at least since the time of Bach.
As a result of the numerical conditions imposed for the sounds of the conventional piano, the strings are submitted to great and varying tensions which require irregular changes in the length of the strings and variation in their tension. This in turn requires that in the sound board, groups of strings be arranged on different planes or layers and that the piano frame be provided with beams, bridges and girders of enormous strength and resistance to hold the strings under the necessarily high tension.
As a consequence, of the conventional method, of forming sound boards, the process of hammering, or "action", i.e. the system of levers required to finally strike the string in different directions, is very complicated; with the result that such devices are made by firms specializing in such units alone, rather than by the piano manufacturer himself.
As will therefore be seen, the construction of the sound board of a piano which provides acurately and with certainty 88 sounds geometrically measured and distinct, is very complicated and difficult.
It is the object of the present invention to provide a novel construction for a piano sound board overcoming the problems and disadvantages of the prior art.